Contact damage resistance of TiN-coated hardmetals: Beneficial effects associated with substrate grinding

SURFACE & COATINGS TECHNOLOGY

卷:275

Article

Yang, J.^1,2  Garcia Marro, F.^1,3  Trifonov, T.³  Oden, M.²  Johansson-Joesaar, M. P.^2,4  Llanes, L.^1,3 

[1] Univ Politecn Cataluna, CIEFMA, Dept Ciencia Mat & Engn Metal Lurg, ETSEIB, E-08028 Barcelona, Spain

[2] Linkoping Univ, Nanostruct Mat, Dept Phys Chem & Biol, IFM, S-58183 Linkoping, Sweden

[3] Univ Politecn Cataluna, CRnE Ctr Res Nanoengn, E-08028 Barcelona, Spain

[4] SECO Tools AB, S-73782 Fagersta, Sweden

关键词: Substrate grinding;    Contact damage resistance;    Coated hardmetal;    Surface integrity;   

DOI  :  10.1016/j.surfcoat.2015.05.028

来源: Elsevier

【 摘 要 】

Contact loading is a common service condition for coated hardmetal tools and components. Substrate grinding represents a key step within the manufacturing chain of these coated systems. Within this context, the influence of surface integrity changes caused by abrasive grinding of the hardmetal substrate, prior to coating, is evaluated with respect to contact damage resistance. Three different substrate surface finish conditions are studied: ground (G), mirror-like polished (P) and ground plus heat-treated (GTT). Tests are conducted by means of spherical indentation under increasing monotonic load and the contact damage resistance is assessed. Substrate grinding enhances resistance against both crack nucleation at the coating surface and subsequent propagation into the hardmetal substrate. Hence, crack emergence and damage evolution is effectively delayed for the coated G condition, as compared to the reference P one. The observed system response is discussed on the basis of the beneficial effects associated with compressive residual stresses remnant at the subsurface level after grinding, ion-etching and coating. The influence of the stress state is further corroborated by the lower contact damage resistance exhibited by the coated GTT specimens. Finally, differences observed on the interaction between indentation-induced damage and failure mode under flexural testing points in the direction that substrate grinding also enhances damage tolerance of the coated system when exposed to contact loads. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

Free